Dissolvable Sleeves for Wiper-Dart Cleaning in Well Completions
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Solution Overview
Problem
Existing wiper darts struggle to completely clean complex completion equipment profiles in hydrocarbon wells, leading to cement and debris deposits that impair equipment function and contaminate formations.
Innovation Solution
A dissolvable protective sleeve is used to cover completion equipment with a uniform profile, allowing wiper darts to effectively clean the liner surface, which is then removed using acid or milling after cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a wiper dart is used to clean the liner surface, then the uniform liner surface is effectively cleaned, but the complex completion equipment profile regions remain inaccessible and trap cement deposits
Solution Approach 1:
A uniform profile insert is introduced as an intermediary component between the wiper dart and the complex completion equipment profile. The insert provides a uniform cleaning surface that the wiper dart can effectively clean, while the insert itself protects the underlying complex profile during the cleaning operation.
Solution Approach 2:
The uniform profile insert is installed beforehand to create a temporary uniform surface that enables effective wiper dart cleaning. After cleaning is complete, the insert is removed to reveal the clean complex equipment profile underneath.
2Adaptability or versatility
If the liner profile includes perpendicular steps and recesses for completion equipment, then the equipment can be installed, but these regions become traps for cement and debris that impair equipment function
Solution Approach 1:
The uniform profile insert acts as a mediator that temporarily covers the complex equipment profile during cleaning operations, allowing the wiper dart to clean without encountering the problematic perpendicular steps and recesses.
Solution Approach 2:
The uniform profile insert is a temporary, disposable component that is installed for the duration of the cleaning operation and then removed. It sacrifices itself to enable the cleaning process without needing to be permanently installed.
3Ease of operation
If a protective sleeve with uniform profile is installed over completion equipment, then the wiper dart can clean effectively, but the sleeve itself must be removed after cleaning
Solution Approach 1:
The mechanical removal process is replaced by using a dissolvable material that can be chemically dissolved by acid or other solvents, eliminating the need for complex mechanical removal operations downhole.
Solution Approach 2:
The physical-chemical parameter of the sleeve material is changed to be soluble in acid or other solvents, allowing the sleeve to be removed by chemical dissolution rather than mechanical means.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures thorough cleaning of completion equipment, preventing deposits and ensuring proper equipment function, while minimizing formation contamination.
Implementation Method 1
The sleeve or insert may be made from a dissolvable material such as aluminium, magnesium alloy, zinc alloy, thermoplastic or other biodegradable material. The sleeve or insert could be removed by dissolving in acid or other solvents, or by milling away.
Data Source
Figure 1~2
AI summary
The invention relates to the use of a sleeve (9) installed in a liner or casing (1) prior to a cementing operation. Completion equipment in the liner/casing creates an irregular inner profile which can cause cement to get trapped. A wiper dart (3) passed down the casing/liner (1) may have difficulty removing all residual cement (5). By using a sleeve or insert (8) in the liner/casing (1), a smooth inner profile (9) may be created which can be cleaned relatively easily by a wiper dart. Once cementing and cleaning are complete, the sleeve (9) may be removed by acid if it is made from a dissolvable material such as aluminium.